In recent years, demand for and interest in a high-resolution, high-quality image service is very high. As an ultra high definition TV (UHDTV) following a HDTV has come into the market, a very realistic high-resolution, high-quality broadcast service is being provided. In a mobile market, a smart phone having an HD level basic screen resolution has also come into the market and, as a result, users' demand for a high-resolution, high-quality image is rapidly increasing. H.264/advanced video coding (AVC) standards used now in various multimedia devices, such as a DTV, a DMB, a DVD, a digital camcorder, an image black box, an IPTV, a smart TV, and a smart phone, are limited in supporting a high-resolution, high-quality image service. For this reason, ITU-T Video Coding Experts Group (VCEG) and ISO/IEC Moving Picture Experts Group (MPEG) have started to standardize high efficiency video coding (HEVC) according to the necessity of a new next generation moving picture compression standard having a higher compression rate and a lower complexity than H.264/AVC and completed Final Draft International Standard (FDIS) of HEVC. HEVC is a next generation image compression standard exhibiting coding efficiency equivalent to about 35% that of H.264/AVC and has attracted considerable attention as a core technology for effectively compressing huge data of HD level images and UHD level images. It is prospected that optimized HEVC software and hardware standards will come into the market through efforts for commercialization of HEVC technology all over the world.
Meanwhile, a trick play means a service providing a function that is capable of reproducing an image after a random time, i.e. enabling random access, and an X speed function, such as an X2 speed and an X4 speed. Since there is a difference between a random access point of HEVC and a random access point of H.264, it is necessary to newly define a category of the random access point of HEVC. In addition, HEVC provides scalability and, therefore, it is necessary to provide a trick play using the same. Furthermore, a conventional CFF media file format specification defines a format for a trick play of H.264/AVC. However, content encoded by HEVC is not defined. Consequently, it is necessary to provide a new format for decoding and a trick play of content encoded by HEVC.
For execution of a trick play, pictures constituting a video stream are classified using a concept of a tier according to dependency between the respective pictures in a conventional AVC/H.264 base. A receiving side decodes and displays only pictures having a specific tier value to provide a trick play. Since HEVC basically provides temporal scalability of a video stream, however, it is necessary to study a method of providing a trick play service using temporal scalability. Moreover, if a user knows providable maximum X speed information, the user may feel convenience in using a trick play. Consequently, it is necessary to study a method of providing providable maximum X speed information to the user.